The invention relates generally to transfection and cell fusion and, more particularly, to a method and apparatus for directing high-voltage currents to a suspension of cells and DNA.
In the biotechnical field, it is sometimes desirable to introduce cloned DNA into mammalian and any other cells using a high-voltage electrical discharge. This method, commonly referred to as "transfection," typically involves creating a suspension of cells in a phosphate-buffered saline (PBS) solution and adding cloned DNA. The suspension is then subjected to a highvoltage pulse from a pulse generator of some kind which causes the cells to take up and express the exogenous DNA. Various pulse generators are available for this purpose, and most supply current in the milliampere range. One unit is available which can apparently produce 40 amperes of current.
The amount of voltage and current required in transfection procedures depends upon the cell and DNA types, and the electrical characteristics must be closely controlled. It has been discovered that some transfection procedures require currents of as much as 125 amps and more. This current requirement is vastly greater than that available from known pulse generators in the biotechnology field.
Known power supplies used in the biotechnology field are incapable of deliverying the required current, and they could not be modified to do so because such power supplies are transistor-driven, and transistors are capable of providing only up to approximately 50 amperes of current. Known power supplies with the capability of generating such high currents are unsuitable for biotechnology applications since they are cost-prohibitive and do not have adequate safety control mechanisms. For example, they are often not designed for frequent human manipulation, and a risk of shock is usually present. A shock from these devices would most likely be lethal.
Even if a high-current power supply is constructed, it must be capable of generating high voltage, high energy, rectangular pulses. Switching the components in such a high-voltage/high-current power supply to create the rectangular pulses is likely to create severe stress on the components and possibly cause damage to the power supply.